Method of preventing skin drying of inks, varnishes, paints, etc.



Patented July 27,, 1 943 IiiUETHOD 01F PREVENTING SKIIN DRYHNG @IF INKS, VARNKSHES, IPAKN'ILS, ETC.

Edward Edwards, lira, (Chicago, liil.

No Drawing. Application August 9, 19410,

I Serial No. 351,968

4 claims. (oi. 21-25) My invention relates to a method of preventing inks, varnishes and other coating pastes and liquids from skinning, gelling and oxidizing.

Considerable waste now occurs in association with the printing and painting trades due to the fact that the pastes and liquids used deteriorate upon exposure to the atmosphere.

The principal object of my invention is to provide an easy and economical method of treating the pastes and liquids with a preservative.

It is now customary in the printing field to clean up the printing press at the end of the day's operations, removing the ink from the rollers, plates and other inked surfaces, and to either cover up the ink fountain or to remove the ink from it. This is done to prevent the ink from drying, which takes place ordinarily within a few hours time. Ink left in a press for several hours usually becomes quite unsuitable for use and must be removed before the press may again be operated. Quite often the press is cleaned up before the lunch hour as there may be some delay later in getting another job on the press.

Several chemical ingredients are now sold for mixing into the ink to slow up the drying to.

into the ink and act upon the whole body of it.

Previously, certain similar materials Were used for retarding the drying of varnish and other finishing liquids. The most efficient of these chemicals have been the polyhydroxy phenols and their derivatives. Pyrocatechol is a di-hydroxy and pyrogallol a tri-hydroxy phenol and both exhibit powerful anti-skinning properties. Guaiacol is a derivative of pyrocatechol in which one of the phenolic groups has been converted to an ether. Its action is less powerful than that of pyrocatechol but still effective when used in quantities that are practical. Guaiacol is available at a price that haspermitted its use as an anti-skinning agent to become widespread.

The use of the phenols, pyrocatechol and pyro-' gallol, is prohibitive at the price at which they are now available.

Another material equally satisfactory for the purpose of this invention is eugenol, a well known compound derived from clove oil and sold by most chemical houses.

This invention involves the use of an ingredient such as eugenol mixed with castor oil or some other non-drying oil as a carrier and as an evaporation preventive agent. Corn, olive, raw linseed and similar non-drying vegetable oils give satisfactory results. The oil added to the basic ingredient cooperates with the basic ingredient to prevent skin drying, reduces the cost, and serves very effectively in holding itself and the anti-oxidant upon whatever surface it is deposited without permitting running or otherwise any movement out of position. It has been found that just a small amount (a fraction of one per cent of the quantity of ink) of the basic material such as eugenol is necessary to keep the ink from drying, gelling and oxidizing when used in a compound with oil and applied according to this invention as a light mist coat to the surface of the ink as compared to the considerable quantity (as much and sometimes more than one part intwenty of the ink) necessary when the material is introduced directly into the ink itself. This process is not only useful in printing shops for presses and ink containers, but als may be used to advantage in a paint shop for preserving paint that has been exposed 'to the atmosphere.

bit

While the proportions of the oil and the antiskinning agent may be varied over a wide range without greatly affecting the results obtained, the use of approximately six parts of oil to four parts of the anti-skinning agent has been found to be economical and otherwise very satisfactory. It has been found that the vegetable oil and the anti-oxidant agent should-each be at least 10% of the complete composition.

In practicing my invention. it isdesirable to employ an air operated spray device of the type used for spray painting. However, an ordinary hand operated pump type of insecticide spray may be used. The liquid compound is applied to the inked portions of the press and to the surfaces of the ink in the ink fountain in a very light spray, The resultant coating is so fine that it is hardly perceptible. A small quantity of the liquid thus goes a long way. The compound is of such a character that it clings to all types of irregular surfaces apparently remaining on raised and pointed areas as evenly as on others. While the spray method of application is much superior to any other because it deposits the preservative evenly and without disturbing the materiaL' the preservative compound may be applied by other means such as a brush or sprinkler can,

In the event that some of the inked portions of the press are not reached by the spray application the press may be operated for several seconds. This will carry the compound to surfaces which are difficult to coat or bring such surfaces within reach. A second light mist coat may again be given the exposed inked areas.

- Following this treatment, the press may be left over night .or for a comparable period without further attention. When operation of-the press is resumed it will work entirely satisfactory. No time will be required for inking the press. Little if any waste is encountered as the very first sheets printed after resumption of operation are usually acceptable. The first few sheets are more likely to be satisfactory however if the plates are not directly coated with the spray but obtain the compound from the rollers when the press is momentarily operated after the spray application.

In applying my method to the preservation of varnishes, enamels and other liquid coatings, a

similar procedure of depositing a very light film of preservative compound to the surface of the material involved is followed. Any such liquid that remains in a half emptied can may be protected by being sprayed with a fine mist of the compound. The surfaces of a varnishing machine of the roller type may be treated with a spray of the inti-skinning compound to do away with the necessity of cleaning up the machine between periods of operation. 7

What I claim as new, and desire to secure by Letters Patent, is:

1. The method of protecting a body of ink or similar material exposed to the atmosphere comprising the application by spray of an extremely light coating of a non-diluting liquid preservative containing a non-drying vegetable oil and at least 10% of an anti-oxidant, to form an effective non-flowing anti-skinning film without adversely affecting the drying and setting qualities of the ink or similar material in its normal use.

2. The method of protecting a body of ink or similar materiahexposed to the atmosphere and which it is desired to re-use, comprising the application by spray upon the full surface of the ink of an extremely light coating of anon-diluting liquid preservative containing a non-drying vegetable oil and an anti-oxidant, to form an efiective non-flowing anti-skinning film without diluting or otherwise adversely affecting the drying and setting qualities of the ink or similar material in its normal use.

3. The method of protecting a body of ink or similar material-exposed to the atmosphere comprising the application by spray of an extremely light coating of a non-diluting. preservative containing a non-drying vegetable oil and eugenol, each of which constitute at least 10% of the composition, to form an efiective antiskinning film without adversely affecting the drying and setting qualities of the ink or similar material in its normal use.

4. The method of protecting a body of ink or similar material exposed to the atmosphere comprising the application by spray of an extremely light coating of a non-diluting preservative containing castor oil and eugenol, each of which constitute at least 10% of the composition,-to

form an effective anti-skinning film without ad- 7 versely afiecting the drying and setting qualities of the ink or similar material in its normal use.

EDWARD EDWARDS. JR. 

